The present invention relates to a process of synthetizing ethylene-tetracarboxylic esters of the formula (I) or (II): ##STR2## starting from malonic compounds of the formula (III): ##STR3## wherein X=COOR, Y=COOR' and R and R', the same or different, are organic groups, inert under the synthesis conditions. There are known methods of preparing esters of the formula (I) or (II), where X=Y=COOR and where R is an alkyl group, starting from malonates and NaOH (25% b.w.) in CH.sub.2 Cl.sub.2, containing tetrabutylammonium bromide and trichlorobromomethane (see German Patent No. 3,031,348), or by electrolytic duplication of the malonate (see U.S. Pat. Nos. 4,076,601 and 4,659,441); these ethylene-tetracarboxylic esters can be used in detergent formulations or for the production of technopolymers. Furthermore, they can be transformed into pinacol derivatives by catalytic hydroxylation with hydrogen peroxide.
The Applicants have now found that it is possible to obtain the same esters by an alternative simpler, quicker and more advantageous process.